Muhammadi and his friend, nightclub bouncer Farhad Mahmud, 35, squirted petrol through the letterbox using a garden sprayer before igniting it, leading to fire breaking out at the base of the stairs.

Flames cut off any escape route for the family who were asleep upstairs at the time as fire and dense smoke filled the three-bedroom property.

Last month, Muhammadi and Mahmud were each found guilty of three counts of murder and two counts of attempted murder in relation to Crook's mother Amanda, 50, and brother Bohdan, 22, who survived.

Muhammadi's girlfriend, Emma Smith, 22, was convicted of three counts of manslaughter but cleared of murder and attempted murder following a six-week trial.

Prosecutors said unemployed Smith "encouraged and goaded" Muhammadi and exchanged hate-filled texts and online messages with Mrs Crook before her death.

Mahmud was sentenced to life with a minimum term of 34 years in prison before being eligible for parole.

Addressing Muhammadi and Mahmud, the judge said that they had been convicted on "overwhelming" evidence.

He said: "No one who heard the evidence in this case will ever forget Mrs [Amanda] Crook's description of how, as he tried to escape, her husband [Mark Crook] became stuck in the bedroom window and how, unable to extricate himself, she had to stand and watch as his lower half was burned."